Fix: improve error handling in upload script for auth failures

scripts/upload_data.py

@@ -12,6 +12,12 @@ def upload_data(repo_id, token, data_dir=".", db_file="rag-kb.db", vector_store_
         print(f"Repository {repo_id} ensures.")
     except Exception as e:
         print(f"Note: Repo creation check: {e}")
+        if "401" in str(e) or "Unauthorized" in str(e):
+            print("\n❌ Error: Authentication failed. Your HF_TOKEN is invalid or expired.")
+            print("Please check your token at https://huggingface.co/settings/tokens")
+            print("You can run this script with a specific token:")
+            print(f"  python3 scripts/upload_data.py --token hf_YOUR_TOKEN")
+            return
 
     # Upload database
     if os.path.exists(db_file):